This invention relates to liquid ring pumps, and more particularly to liquid ring pumps in which the inner surfaces of the housings are shaped to reduce fluid friction losses in the pumps.
Liquid ring pumps are well known as shown, for example, by Sommer U.S. Pat. No. 1,525,332 and Haavik U.S. Pat. No. 4,613,283. Russian inventor's certificate 529,295 points out that fluid friction in such pumps can be reduced by making the housing and turbine wheel of trapezoidal shape in axial section. According to this reference, by shaping the pump in this way the area of the housing surface contacted by the liquid is reduced, thereby reducing hydrodynamic loss in the pump.
The pump design shown in the above-mentioned Russian inventor's certificate results in several parts having very complex shapes. For example, the central housing element varies in axial length around the pump. As a consequence of this aspect of the shape of the central element, the faces of the end housing elements which abut the central element do not lie in planes perpendicular to the rotor axis. The pump of the Russian inventor's certificate would therefore be relatively difficult and expensive to make. In addition, while the trapezoidal shape shown in the Russian inventor's certificate may reduce hydrodynamic loss in the pump to some degree, there is a need for further reduction in such loss.
In view of the foregoing, it is an object of this invention to provide improved liquid ring pumps.
It is a more particular object of this invention to provide liquid ring pumps with reduced hydrodynamic loss due to contact between the recirculating liquid ring in the pump and the stationary housing of the pump.